Identification and molecular characterization of a 27 kDa Shigella flexneri invasion plasmid antigen, IpaJ
| Autor: | Jerry M. Buysse, Malabi M. Venkatesan, Donna S. Dunyak, Antoinette B. Hartman |
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| Rok vydání: | 1998 |
| Předmět: |
Sequence analysis
Recombinant Fusion Proteins Blotting Western Guinea Pigs Molecular Sequence Data Restriction Mapping Virulence medicine.disease_cause Microbiology Shigella flexneri Plasmid medicine Animals Humans Shigella Amino Acid Sequence RNA Messenger Gene Cells Cultured Antigens Bacterial biology Base Sequence biology.organism_classification Molecular biology Fusion protein Open reading frame RNA Bacterial Infectious Diseases Gene Expression Regulation Mutagenesis Sequence Analysis HeLa Cells Plasmids |
| Zdroj: | Microbial pathogenesis. 23(6) |
| ISSN: | 0882-4010 |
| Popis: | Shigella species and enteroinvasive Escherichia coli contain a core set of virulence genes whose coordinated expression results in the invasion of host colonic epithelial cells and the dysenteric syndrome. A number of virulence determinants are carried by the 230 kb invasion plasmid found in all virulent strains of Shigellae. Many of these invasion plasmid genes encode immunogens that are recognized by convalescent serum, including proteins that mediate the invasion (IpaB, IpaC, IpaD) and cell spreading (VirG or IcsA and IcsB) phenotypes. In this report, we describe the molecular characterization of a novel invasion plasmid antigen from Shigella flexneri, designated IpaJ. The ipaJ gene encodes a 780 bp open reading frame (ORF), separated from the ipaR (virB) stop codon by 944 bp. The predicted amino acid sequence for IpaJ revealed a consensus signal peptide for protein export. TnphoA mutagenesis of the ipaJ ORF confirmed the presence of export signal sequences in IpaJ. Unlike ipaBCDA genes, transcription analysis of ipaJ indicated that the gene is not expressed in a temperature-dependent fashion. The IpaJ protein was expressed and purified as a His6-tagged fusion protein that reacted with convalescent sera in Western blot analyses, confirming its identification as a Shigella immunogen. Construction and phenotypic characterization of ipaJ mutants in two serotypes of S. flexneri showed that the mutants were not compromised in their ability to invade cultured epithelial cells or to form plaques on BHK cell monolayers. In addition, the ipaJ mutants were Sereny positive indicating a capacity for intercellular dissemination; however, in the limited number of guinea-pigs tested, the keratoconjunctivitis reaction appeared attenuated. |
| Databáze: | OpenAIRE |
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